Single-Molecule Detection with Lightguiding Nanowires: Determination of Protein Concentration and Diffusivity in Supported Lipid Bilayers

• DOI: 10.1021/acs.nanolett.9b02226
• Publication Date: 2019-08-01T20:07:53Z
• Authors: Damiano Verardo; Björn Agnarsson; Vladimir P. Zhdanov; Fredrik Höök; Heiner Linke
• Keywords: Cholera Toxin; Light; Nanowires; Cell Membrane; Lipid Bilayers; G(M1) Ganglioside; 02 engineering and technology; Single Molecule Imaging; Microscopy, Fluorescence; Semiconductors; Nanotechnology; 0210 nano-technology; Protein Binding

Determining the surface concentration and diffusivity of cell-membrane-bound molecules is central to understanding numerous important biochemical processes taking place at cell membranes. Here we use high aspect ratio lightguiding properties semiconductor nanowires (NWs) detect presence single freely diffusing proteins bound a lipid bilayer covering NW surface. Simultaneous observation light-emission dynamics hundreds individual NWs occurring on time scale only few seconds interpreted using analytical models employed determine both cholera toxin subunit B (CTxB) GM1 gangliosides in supported (SLB) concentrations down below one CTxB per μm2. In particular, decrease was observed with increasing content SLB, suggesting multivalent binding GM1. The capability makes method compatible conventional epifluorescence microscopy, it shown work well for photostable photosensitive dyes. These features make concept an interesting complement existing techniques studying low-abundance molecules, expanding rapidly growing various bioanalytical sensor applications live studies.